A PSS parameter setting method and system adaptable to multiple operating modes

Abstract

The present invention relates to a PSS parameter setting method and system that is adaptable to multiple operating mode adjustments. The method comprises: obtaining the difference in phase-frequency characteristics under different operating modes; carrying out on-site generator excitation system phase-frequency characteristic tests to obtain actual phase-frequency characteristic results under the current operating mode; comparing the pre-calculated results of the phase-frequency characteristics under the current operating mode and other operating modes, and adopting an under-compensation mode or an over-compensation mode according to the results; calculating the phase-frequency characteristics after compensation for each operating mode, adjusting the over-compensation and under-compensation angles of the lag phase at this frequency point, and performing local optimization adjustment on the set PSS parameters. The present invention can improve the adaptability of the set PSS parameters under multiple operating modes, prevent the damping weakening or negative damping effect caused by the traditional single setting method after the operating mode adjustment, and improve the system damping to prevent the system from dynamic instability.

Description

Technical Field

[0001] The invention relates to the field of generator excitation system PSS parameter setting, and specifically provides a PSS parameter setting method and system adaptable to adjustments in multiple operating modes. Background Art

[0002] The existing generator excitation system PSS parameter adjustment is based on the phase-frequency characteristics results of field tests using genetic algorithms, frequency methods, etc. However, the field test results are carried out under a certain operating mode. When the operating mode is adjusted and the external grid structure changes, the original compensation effect will deteriorate. In extreme cases, the PSS may even provide negative damping, causing the system to become dynamically unstable.

[0003] Therefore, there are great limitations in adjusting PSS parameters based solely on test results. It is particularly unsuitable for small and medium-sized hydropower units whose transmission lines and operating modes are frequently adjusted. Moreover, due to the limitations of site conditions and grid operation modes, it is impossible to conduct all phase-frequency characteristics of the generator excitation system under various operating modes on site. Therefore, it is necessary to solve the current difficulties faced by PSS parameter adjustment and improve the adaptability of the adjusted PSS parameters. Summary of the Invention

[0004] The starting point of the present invention is to solve the problem that the current PSS parameter setting is limited to the operating mode during the test, to comprehensively consider the possible multiple operating modes, and to improve the adaptability of PSS under multiple operating modes.

[0005] The technical solution adopted in the present invention is:

[0006] A PSS parameter setting method adapted to various operating modes includes the following steps:

[0007] Step (1) obtaining the phase-frequency characteristic differences under different operating modes;

[0008] Step (2) conducting an on-site generator excitation system phase-frequency characteristic test to obtain actual phase-frequency characteristic results under the current operating mode;

[0009] Step (3) comparing the pre-calculated results of the phase-frequency characteristics under the current operating mode with those under other operating modes, and adopting an under-compensation mode or an over-compensation mode according to the results;

[0010] Step (4) calculates the phase-frequency characteristics after compensation for each operating mode, adjusts the over- and under-compensation angles of the lag phase at this frequency point, and performs local optimization adjustment on the set PSS parameters.

[0011] Furthermore, in step (1), before conducting the field test, various possible operating modes of the generator set are analyzed, the short-circuit reactance of the transmission line and the system under the external operating mode is obtained, and the phase-frequency lag characteristics under different operating modes are pre-calculated using the Hefren-Phillips model to obtain the differences in phase-frequency characteristics under different operating modes.

[0012] Furthermore, in step (3), if the phase-frequency characteristic of the current mode lags behind other modes, an under-compensation mode is adopted, and the under-compensation angle is half of the maximum phase difference under each operating mode. If the current operating mode is ahead of other modes, an over-compensation mode is adopted, and the over-compensation angle is half of the maximum phase difference under each operating mode.

[0013] Furthermore, in step (4), the phase-frequency characteristics after compensation of each operating mode are calculated to ensure that the compensation effect is between -10° and 45° as specified in the standard. If a frequency point exceeds this range in any mode, the over- or under-compensation angle of the lag phase at this frequency point is adjusted, and the set PSS parameters are locally optimized.

[0014] Furthermore, in step (1), the Heflen-Phillips model is used to pre-calculate the phase-frequency lag characteristics under different operating modes, and the relationship between the electromagnetic torque and the power angle is calculated as formula (1):

[0015]

[0016] Electromagnetic torque ΔT e2 and potential ΔE' q The phase is the same, so the lagging phase characteristic adopts the transient potential ΔE' q The phase characteristic relative to the power angle Δδ is expressed as follows (2):

[0017]

[0018] Obtain the difference in phase-frequency characteristics under different operating modes; the larger the external contact reactance, the smaller the phase-frequency lag characteristic;

[0019] The calculation process of K1-K6 is shown in the following equations (3)-(8):

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026] U to is the generator terminal voltage, U do 、U qo are the direct-axis and quadrature-axis components of the generator terminal voltage, I do , I qo are the direct-axis and quadrature-axis components of the generator terminal current, X d 、X q is the generator direct-axis and quadrature-axis synchronous reactance, X' d 、X' q is the generator direct-axis and quadrature-axis transient reactance, X e K is the system contact reactance; A Excitation system magnification, T d0 'Rotor open-circuit subtransient time constant, φEX phase-frequency characteristic; -a represents inverse sine.

[0027] The present invention also relates to a PSS parameter setting system adaptable to multiple operating modes, comprising a collector and a processor;

[0028] The collector collects the generator excitation system parameters, and the processor processes them according to the above method.

[0029] The present invention also relates to an electronic device, comprising a memory, a processor, and a computer program on the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0030] The present invention also relates to a non-transitory computer-readable storage medium having a computer program stored thereon, which implements the steps of the above method when executed by a processor.

[0031] The present invention can improve the adaptability of the adjusted PSS parameters under various operating modes, prevent the damping weakening or negative damping effect caused by the traditional single adjustment method after the operating mode is adjusted, and improve the system damping to prevent the system from dynamic instability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a structural block diagram of a system according to an embodiment of the present invention;

[0033] Figure 2 is a flow chart of the Hefren-Phillips model involved in the method of the embodiment of the present invention;

[0034] Figure 3 2 is a diagram showing the difference in phase-frequency characteristics under different operating modes of the method according to the embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0036] Unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by a person of ordinary skill in the art. The terms "first," "second," and similar terms used in this embodiment do not indicate any order, quantity, or importance, but are simply used to distinguish different components. The terms "include" or "comprises" and similar terms mean that the element or object preceding the term includes the elements or objects listed after the term and their equivalents, but do not exclude other elements or objects. "Installed," "connected," and "connected" should be understood broadly. For example, they can mean fixed, detachable, or integral; they can be directly connected, indirectly connected through an intermediary, or internally connected between two components. "Up," "down," "left," "right," "horizontally," and "vertically" are used only with respect to the orientation of components in the drawings. These directional terms are relative concepts and are used for description and clarification relative to the actual position of the components in the drawings. They may change accordingly depending on the orientation of the components in the drawings.

[0037] like Figure 1 As shown, the PSS parameter setting system adapted to various operation modes of this embodiment includes a collector, a processor, a display and an input terminal. The collector collects generator excitation system data.

[0038] The display shows the processing process and final results, and can also be used by the operator to control the interface. A memory can also be set to store the corresponding collected data and processing results. The input terminal can be an existing keyboard or touch screen.

[0039] It should be noted that the division of the various modules of the above devices is merely a division of logical functions. In actual implementation, they may be fully or partially integrated into a single physical entity, or physically separated. Furthermore, these modules may be implemented entirely in the form of software called by processing elements, entirely in the form of hardware, or partially in the form of software called by processing elements, while others may be implemented in the form of hardware.

[0040] The processing element described herein may be an integrated circuit having signal processing capabilities. In the implementation process, each step of the above method or each module above may be completed by hardware integrated logic circuits in the processor element or software instructions.

[0041] For example, the above modules may be one or more integrated circuits configured to implement the above methods, such as one or more specific integrated circuits, one or more microprocessors, or one or more field programmable gate arrays. For another example, when a module is implemented by scheduling program code on a processing element, the processing element may be a general-purpose processor, such as a central processing unit or other processor capable of invoking program code. For another example, the modules may be integrated together and implemented as a system-on-chip.

[0042] The above-mentioned processor can be a general-purpose processor, including a central processing unit, a network processor, etc.; it can also be a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component.

[0043] Optionally, an embodiment of the present application further provides a storage medium, in which instructions are stored, and when the storage medium is run on a computer, the computer executes the method of the embodiment shown above.

[0044] Optionally, an embodiment of the present application further provides a chip for executing instructions, wherein the chip is used to execute the method of the embodiment shown above.

[0045] According to the Hefren-Phillips model editing control execution program, the relationship between electromagnetic torque and power angle can be calculated as formula (1):

[0046]

[0047] Electromagnetic torque ΔT e2 and potential ΔE' q The phase is the same, so the lagging phase characteristic can be expressed as the transient potential ΔE' q The phase characteristic relative to the power angle Δδ is expressed as shown in formula (2):

[0048]

[0049] When the generator operating state is known and the system parameters are determined, the phase lag characteristics of the generator excitation system can be obtained by inputting parameter data.

[0050] Based on the above system, the PSS parameter tuning method adapted to various operating modes is carried out as follows:

[0051] Step (1) Before conducting the field test, various possible operating modes of the generator set are analyzed. Various operating modes generally include different line transmission in isolated and networked modes. The collector obtains parameters such as the transmission line and system short-circuit reactance as well as the generator and excitation system under the external operating mode. The processor uses the Heflen-Phillips model to pre-calculate the phase-frequency lag characteristics under different operating modes. The relationship between the electromagnetic torque and the power angle can be calculated as formula (1):

[0052]

[0053] Electromagnetic torque ΔT e2 and potential ΔE' q The phase is the same, so the lagging phase characteristic can be expressed as the transient potential ΔE' q The phase characteristic relative to the power angle Δδ is expressed as follows (2):

[0054]

[0055] Obtain the difference in phase-frequency characteristics under different operating modes. The larger the external contact reactance, the smaller the phase-frequency lag characteristic.

[0056] Figure 2 In the calculation process of K1-K6, the following equations (3)-(8) are shown:

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063] In the above formula: U to is the generator terminal voltage, U do 、U qo are the direct-axis and quadrature-axis components of the generator terminal voltage, I do , I qo are the direct-axis and quadrature-axis components of the generator terminal current, X d 、X q is the generator direct-axis and quadrature-axis synchronous reactance, X' d 、X' q is the generator direct-axis and quadrature-axis transient reactance, X e K is the system contact reactance; A Excitation system magnification, T d0'Rotor open-circuit subtransient time constant, φEX phase-frequency characteristic; -a represents inverse sine.

[0064] Step (2) conducts an on-site generator excitation system phase-frequency characteristic test, adds a white noise signal to the noise signal point in the excitation system through a noise signal meter, and collects the machine-end voltage signal. The phase difference between the two is the actual test phase-frequency characteristic, and the collector obtains the actual phase-frequency characteristic result under the current operating mode.

[0065] Step (3) compares the pre-calculated phase-frequency characteristics of the current operating mode with those of the other operating modes. If the phase-frequency characteristics of the current mode lag behind those of the other modes, an undercompensation mode is used, and the undercompensation angle is half of the maximum phase difference under each operating mode. If the current operating mode leads the other modes, an overcompensation mode is used, and the overcompensation angle is half of the maximum phase difference under each operating mode. In this embodiment, if the calculated lag phase of the current mode is greater than that of the other modes, it is lagging; otherwise, it is leading.

[0066] Step (4) calculates the phase-frequency characteristics after compensation for each operating mode, calculates the actual compensation phase according to the PSS mathematical model based on the setting parameters, and ensures that the compensation effect is between -10° and 45° as specified in the standard. If a frequency point exceeds this range in any mode, the over- or under-compensation angle of the lag phase at this frequency point is adjusted, and the setting PSS parameters are locally optimized.

[0067] Figure 3 In order to calculate the phase-frequency characteristics under typical different line lengths, real-time electrical data such as generator terminal active power, reactive power, terminal voltage, etc. are collected, and parameters such as generator AC and DC axis reactance and transmission line parameters are collected. Figure 2 The K1-K6 values are calculated by the formula and substituted into formula (2):

[0068]

[0069] The calculated phase-frequency characteristics are considered. Considering both normal grid-connected transmission and long circuitous line transmission, the phase-frequency characteristics under each mode are calculated to obtain the phase deviation. On-site, the actual phase-frequency characteristics are obtained by adding a white noise signal and measuring the phase difference between the generator-end voltage. The pre-calculated phase-frequency characteristics under the current operating mode are compared with those under other operating modes. If the current mode's phase-frequency characteristics lag behind those under other modes, undercompensation is used, with the undercompensation angle being half the maximum phase difference under each mode. If the current mode leads those under other modes, overcompensation is used, with the overcompensation angle being half the maximum phase difference under each mode. The actual compensation phase is calculated based on the PSS mathematical model according to the set parameters, ensuring that the compensation effect is within the standard range of -10° to 45°. If a frequency point under any mode exceeds this range, the over- and undercompensation angles of the phase lag at that frequency point are adjusted, and the PSS parameters are locally optimized.

[0070] It can be seen that the present invention adjusts the PSS parameters by under-compensation or over-compensation based on the pre-calculated results of the phase-frequency characteristics under different operating modes and the phase-frequency characteristics tested in the current operating mode, thereby expanding the adaptability range of the adjusted PSS parameters.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A PSS parameter setting method adapted to various operating modes, characterized by: The steps include: Step (1) obtaining the phase-frequency characteristic differences under different operating modes; Step (2) conducting an on-site generator excitation system phase-frequency characteristic test to obtain actual phase-frequency characteristic results under the current operating mode; Step (3) comparing the pre-calculated results of the phase-frequency characteristics under the current operating mode with those under other operating modes, and adopting an under-compensation mode or an over-compensation mode according to the results; Step (4) calculates the phase-frequency characteristics after compensation for each operating mode, adjusts the over-compensation and under-compensation angles of the lag phase at this frequency point, and performs local optimization adjustment on the set PSS parameters; In step (1), before conducting the field test, various possible operating modes of the generator set are analyzed, the short-circuit reactance of the transmission line and the system under the external operating mode is obtained, and the phase-frequency lag characteristics under different operating modes are pre-calculated using the Hefren-Phillips model to obtain the differences in phase-frequency characteristics under different operating modes; In step (1), the Hefren-Phillips model is used to pre-calculate the phase-frequency lag characteristics under different operating modes, and the relationship between the electromagnetic torque and the power angle is calculated as formula (1): Electromagnetic torque ΔT e2 and potential ΔE' q The phase is the same, so the lagging phase characteristic adopts the transient potential ΔE' q The phase characteristic relative to the power angle Δδ is expressed as follows (2): Obtain the difference in phase-frequency characteristics under different operating modes; the larger the external contact reactance, the smaller the phase-frequency lag characteristic; The calculation process of K1-K6 is shown in the following equations (3)-(8): U to is the generator terminal voltage, U do 、U qo are the direct-axis and quadrature-axis components of the generator terminal voltage, I do , I qo are the direct-axis and quadrature-axis components of the generator terminal current, X d 、X q is the generator direct-axis and quadrature-axis synchronous reactance, X' d 、X' q is the generator direct-axis and quadrature-axis transient reactance, X e K is the system contact reactance; A Excitation system magnification, T d0 'Rotor open-circuit subtransient time constant, φEX phase-frequency characteristic; -a represents inverse sine.

2. The method according to claim 1, wherein: In step (3), if the phase-frequency characteristic of the current mode lags behind other modes, the under-compensation mode is adopted, and the under-compensation angle is half of the maximum phase difference under each operating mode. If the current operating mode is ahead of other modes, the over-compensation mode is adopted, and the over-compensation angle is half of the maximum phase difference under each operating mode.

3. The method according to claim 1, wherein: In step (4), the phase-frequency characteristics after compensation of each operating mode are calculated to ensure that the compensation effect is between -10° and 45° as specified in the standard. If a frequency point exceeds this range in any mode, the over- or under-compensation angle of the lag phase at this frequency point is adjusted, and the set PSS parameters are locally optimized.

4. A PSS parameter setting system adapted to various operating modes, characterized by: Including collector and processor; The collector collects the generator excitation system parameters, and the processor processes them according to the method described in any one of claims 1 to 3.

5. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 3 are implemented.

6. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 3 are implemented.

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